The following Non-Patent Document 1 discloses a lidar that generates pulses of transmission light by using as a light modulator an acoustooptic (AO) device driven by a pulse.
In addition, the following Patent Document 1 discloses a lidar that uses an optical fiber as a propagation path of light within the lidar. Considering that the peak power of the transmission light is limited owing to nonlinear optical effect called stimulated Brillouin scattering that occurs within the optical fiber, the lidar implements high SN ratio measurement by increasing transmission power by using a plurality of CW laser light sources with different wavelengths.
Incidentally, the lidar achieves the high SN ratio by carrying out signal separation processing that separates the received light for the individual wavelengths with a wavelength separation device, by performing coherent detection processing by combining the received light for the individual wavelengths and local oscillation light for the individual wavelengths, and by carrying out integral processing of the individual coherent detection signals.